1. Field of the Invention
The present invention relates to a speed control device for a derailleur type bicycle and, in particular, to a speed control device including an operation lever that a user can pivot in a first direction to pull a cable that controls the derailleur and in a second direction to release the cable.
2. Description of the Related Art
U.S. Pat. Nos. 5,213,005; 5,361,645; 5,479,776 and 6,220,111 disclose a speed control device including one operation lever that the user can use to up-shift the speed and another operation lever to down-shift the speed. However, such speed control device has the disadvantage that the operator could easily operate the wrong lever in a speed change operation.
U.S. Pat. No. 5,287,766 shows a speed control device which utilizes an operation lever for up-shifting and down-shifting the speed. The speed control device is particularly mounted on straight handlebar type bicycles. In spite of the advantage of the speed control device employing one operation lever as discussed in the proceeding, it is believed that there is a need for improvement in the field of speed control devices and more specifically for use in curved handlebar type bicycles.
The present invention is, therefore, intended to obviate or at least alleviate the problems encountered in the prior art.